Indonesia has recommended closer scrutiny of automated control systems, better design of flight deck alerts and accounting for a more diverse pilot population after last year’s fatal crash of a Lion Air Boeing 737 MAX, the Seattle Times reported on Friday.
The newspaper received an advance copy of the final report on the October 29 crash in which all 189 people on board were killed.
Less than five months after the Lion Air accident, an Ethiopian Airlines 737 MAX also crashed, leading the plane to be grounded worldwide and sparking a corporate crisis at Boeing, the world’s biggest planemaker.
Indonesian investigators on Wednesday told families of the victims that a mix of factors contributed to the crash, including mechanical and design issues and a lack of documentation about how systems would behave.
“Deficiencies” in the flight crew’s communication and manual control of the aircraft contributed to the crash, as did alerts and distractions in the cockpit, according to slides presented to the families.
The final report said the first officer was unfamiliar with procedures and had shown issues in his handling of the aircraft during training, according to the Seattle Times.
When the aircraft encountered airspeed-reading problems after take-off, the first officer had to be asked twice by the captain to perform the checklist and it took him four minutes to find it in the quick reference handbook, the newspaper said.
The report also found that a critical sensor providing data to an anti-stall system had been miscalibrated by a repair shop in Florida and that there were strong indications that it was not tested during installation by Lion Air maintenance staff.
Lion Air should have grounded the plane following faults on earlier flights, the report said and added that 31 pages were missing from the airline’s October maintenance logs.
Lion Air did not respond to a request for comment.
In the report, Indonesian regulators recommended a redesign of the anti-stall system known as MCAS that automatically pushed the plane’s nose down, leaving pilots fighting for control.
In a statement on Friday, Boeing vowed to prevent the kind of crashes that killed more than 300 people in Indonesia and in Ethiopia.
Boeing’s President and CEO Dennis Muilenburg said said the company is addressing the committee’s safety recommendations and working to enhance the safety of the 737 Max jet “to prevent the flight control conditions that occurred in the accident from ever happening again.”
Muilenburg said the aircraft and its software are receiving “an unprecedented level of global regulatory oversight, testing and analysis. This includes hundreds of simulator sessions and test flights, regulatory analysis of thousands of documents, reviews by regulators and independent experts and extensive certification requirements.”
According to the report, Boeing’s safety assessment assumed pilots would respond within three seconds of a system malfunction but on the accident flight and one that experienced the same problem the evening before, it took both crews about eight seconds to respond, the Seattle Times said.
Boeing had reasoned that MCAS could be countered by a pilot pulling back on the control column alone, but events and subsequent tests showed that cut-out switches needed to be used, the paper cited the report as saying.
In December 2018, accident investigators and Boeing conducted a simulator test and found that after just two activations of MCAS, without counteraction from the pilot, the control column became “too heavy” to move, the newspaper said.
The final report will be released publicly on Friday. Boeing has said it cannot comment before the release of the report.
A panel of international air safety regulators this month also faulted Boeing for assumptions it made in designing the 737 MAX and found areas where Boeing could improve processes.